/**
 * Copyright (C) 2011 Angelo Zerr <angelo.zerr@gmail.com>, Pascal Leclercq <pascal.leclercq@gmail.com>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package fr.opensagres.xdocreport.converter.internal.xslt;

import java.io.InputStream;

import javax.xml.transform.Source;
import javax.xml.transform.TransformerException;
import javax.xml.transform.URIResolver;
import javax.xml.transform.stream.StreamSource;

/**
 * Abstract {@link URIResolver} which check if {@link InputStream} return by
 * {@link AbstractURIResolver#getInputStream(String, String)}is not null.
 * 
 */
public abstract class AbstractURIResolver implements URIResolver {

	public Source resolve(String href, String base) throws TransformerException {
		InputStream in = getInputStream(href, base);
		if (in == null) {
			throw new TransformerException("Resource does not exist. \"" + href
					+ "\" is not accessible.");
		}
		return new StreamSource(in);
	}

	/**
	 * Returns the input stream.
	 * 
	 * @param href
	 * @param base
	 * @return
	 */
	protected abstract InputStream getInputStream(String href, String base);

}
